The present invention relates generally to connectors for interconnecting components of a spinal column corrective device such as longitudinal members, hooks, and/or pedicle screws, and more particularly to a cross-link or transverse connector which is adjustable longitudinally to accommodate a variety of spacings between such components.
Longitudinal members of spinal column corrective devices generally extend longitudinally along the spinal column. Each longitudinal member, which may consist of a rod or a plate, for example, is typically attached to the spinal column with hooks or pedicle screws which are connected to the longitudinal member. The longitudinal members may be connected together using transverse connectors. Each transverse connector forms a bridge between two longitudinal members to strengthen the overall structure of the spinal column corrective device and provide a desired spacing between longitudinal members.
The present invention is a transverse connector for interconnecting components of a spinal column corrective device, for example, a pair of longitudinal members which are connected to vertebrae of a spinal column. As is further explained below, the present invention might be readily adapted to interconnect a longitudinal member and a pedicle screw, a pair of screws, a longitudinal member and a hook, a pair of hooks, or a pedicle screw and a hook. One embodiment of the present transverse connector generally includes a first member which is adjustably connected to a second member to provide a plurality of selectable spacings between the longitudinal members. The first member includes a body portion having retaining surfaces for engaging similar retaining surfaces on the body portion of the second member, an intermediate portion extending from the body portion having an opening for receiving a clamp or set screw, and a connector portion extending from the intermediate portion for engaging the longitudinal member. When the set screw is turned into the intermediate portion opening, it clamps a first longitudinal member within the first member connector portion. The second member also includes an intermediate portion extending from the body portion having an opening for receiving a clamp or set screw, and a connector portion extending from the intermediate portion for engaging a second longitudinal member. When the set screw is turned into the intermediate portion opening, it clamps the second longitudinal member within the second member connector portion.
The first and second members are connected to one another by a clamp such that when the clamp is in a tightened position, the retaining surfaces of the first and second member engage one another to lock the members in position relative to one another, thereby fixing the distance between the longitudinal members. When the clamp is in a loosened position, the first and second members may remain connected to one another while the retaining surfaces are spaced apart from one another, and the members are adjusted longitudinally relative to one another to a different position. During adjustment, guides extending from the body portion of the second member maintain the first and second members in alignment.
The transverse connector of the present invention may be attached to the longitudinal members of a spinal column corrective device after the longitudinal members have been fastened to the vertebrae of the spinal column. The clamp of the present invention is loosened so that the first and second members may be adjusted relative to one another longitudinally. The members are adjusted until the distance between the two connector portions roughly corresponds to the distance between the longitudinal members. The set screws are backed out of their respective openings. The connector portions are then placed into engagement with the longitudinal members, and the set screws are turned into their respective openings to engage the longitudinal members and clamp the longitudinal members against the connector portions. The distance between the longitudinal members may be adjusted, if desired, as described above. Once a desired spacing is achieved, the clamp is tightened to lock the first and second members in position relative to one another.